Field of the Invention
The present invention relates to the field of the image analysis.
Description of the Related Art
In the field of the image analysis, a common operation provides for comparing two images in order to find the relation occurring therebetween in case both the images include at least a portion of a same scene or of a same object.
Known methods for determining whether two images display the same object provide for selecting a set of so-called interest points in the first image and then matching each interest point of the set or a subset thereof to a corresponding interest point in the second image (generally, some of the selected interest points of the set may not be matched, because of ambiguities). The selection of which point of the first image should become an interest point is carried out by taking into consideration image features in the area of the image surrounding the point itself.
As it is well known to those skilled in the art, if a matching between an interest point of the first image and a corresponding interest point of the second image is correct, in the sense that both interest points correspond to a same point of a same object (depicted in both images), such interest point match is referred to as “inlier”.
Conversely, if a matching between an interest point of the first image and a corresponding interest point of the second image is incorrect, in the sense that the two interest points do not correspond to a same point of the same object, such interest point match is referred to as “outlier”.
Therefore, in order to obtain a reliable result, a procedure capable of distinguishing the inliers from the outliers is advantageously performed after the interest point matches have been determined.
Several examples of procedures of this type are already known in the art, such as for example the image comparison method disclosed in the patent application WO 2012/100819 in the name of the same present Applicant.
Another common operation in the field of the image analysis provides for comparing video shots, or comparing a single image to images of a video shot in order to find the relation occurring therebetween in case both the video shots or both the image and the video shot include at least a portion of a same scene or of a same object.
For example, “Efficient video search using image queries” by A. Araujo, M. Makar, V. Chandrasekhar, D. Chen, S. Tsai, H. Chen, R. Angst, B. Girod, IEEE International Conference on Image processing, October 2014, discloses a method of comparing images to video shots which checks geometric consistency using the Random sample consensus (RANSAC) iterative method.
The method disclosed in “Segmenting, modeling, and matching video clips containing multiple moving objects” by F. Rothganger, S. Lazebnik, C. Schmid, & J. Ponce, IEEE Transactions on Pattern Analysis and Machine Intelligence, 29(3), 2007, pages 477-491, provides a method for the identification of shots that depict the same scene in a video clip. In this case as well, geometric consistency is checked using the RANSAC method.